System of control



R. E. HELLMUND'.

SYSTEM 0F CONTROL.

l APPLICATIONHLEDSEPLT.19|?. 1,361,994. Patented Dec. 14, 1920.

2 SHEETS-SHEET R. E. HELLMUND.

SYSTEM 0F CONTROL.

APPLICATION FILED SEPT. 7. 1917.

1,361,994, y Patented Dec. 14, 1920.

2 SHEETS-SHEET 2.

wlTNEssEs: INVENToR I BY f MAQNEY UNITED rArENT orrlcn.

RUDOLF E. HELLIVIUND, OF SNISSV'ALE, PENNSYLVANIA, AS-SIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING Of/IPANS, .A CORPORATION OF PENN- SYLVAN IA.

SYSTEM OF CONTROL.

Application filed September 7, 1917.

To @ZZ /wzomz't may concern:

Be it known that l, RUDOLF lil. HELLMUND, a citizen ot the German Empire, and a resident of Swissvale, vin the county oi' llcza'heny and State of Pennsylvania, have in- 'vented a new and useful Improvement in Systems oi? (lontrol, o'll which the i'fol'mringl is a specilication.

My invention relates to systems oi control and especially to the automatic control ot electric railway vehicles, and the like, under coastinO' conditions.

The object of my invention is to provide a system of the above-indicated character which shall he relatively simple in arrangement and reliable in operation, wherein the main-machine field excitation shall be automatically varied to produce a predetermined relation of supply-circuit voltage and ma- Ichine voltage under normal-speed coasting` conditions, and wherein such automatic variation shall be inherently counteracted under relatively high-speed coasting' conditions.

A t'urther object of my invention is to combine, with the previously outlined system, relay means for preventing; the connection of the machine to the supply circuit during` the coasting period until substantially stable main-iield excitation conditions obtain.

My invention may best be understood by reterence to the accompanying' drawing, wherein Figure l is a diagrammatic View of the main circuits ot a system ot control embodying; the invention; Figi'. 2 is a dian'i'anr matic View ot an auxiliary governing system or the main circuits that are shown in f and Fig. 3 is a diagrammatic View a modiiied system embodyingmy invention.

Referring' to Fig'. l of the drawing, the system shown comprises supply-circuit conductors Trolley and Ground; a plurality oli maia dynamo-electric machines respectively having commutator-type armatures A l and AQ and iield windings Fl and ot the series type; a. motor-generator set l or the like that is driven from the supply circuit for the purpose of providing' an auxiliary excitation for the main field windings; a plurality ot resistors 2, 3, 4t and 5, which are connected in circuit in a manner to ne clescriced d which may he varied in activecircuit value by means of a controller 6 hay- Specification of Letters Patent.

Patented Dec. 14, 1920.

serial No. 190,135.

ing an actuating mechanism. 7; a torquemotor relay device P3 'for the purpose of automatically regulating certain machine circuits in accordance with the relation ci supplys circuit if'oltage to main-machine voltage during the coasting period; a plurality oi switches 9, i() and ll for effecting certain main and auxiliary circuit connections; and main-ieldtiux relay l2 'for a purpose to hc set forth.

The motor generator set l driv' o1 comprises a ig or motor armature 20, upon the shaft which an exciting` or generator armature 22 is also mounted. A series-related iield winding 23 is provided for the drivii'uij armature 20, while the exciting' armature has a plurality of lielil windings 2li and 25 cumulatively-related during' regeneration, which are respectively energized in accordance with the load current ot the motorgenerator set and the main-armature current. The main-current-excited iield winding 25 is ',c-r fera-.bly shunted by a resistor 26, and the switch l0, when closed, is adapted to short circuit the iield winding'. The switch ll performs a similar function with respect to the allied auxiliary lield winding` 24h.

The controller." (i preferably comprises a drum body 27 upon which are mounted a plurality ot contact segments 28, 29, 30 and for gradually varying' the active-circuit values of the resistors 2, 5S, 4L and 5 in accorde-nre with the movements of the controller.

The actuating' mechanism 7 for the controller G is a familiar electric:lily-controlled, pncumatirally-operated type, comprising,` a pinion which secured to the opera-ting` shaft 36 ot the controller to mesh with a horizontally-movable rack member 23.7, the opposite ends of which constitute pistons and 39 that travel within appropriate operating` cylinders e() and 4l, respectively, A normally closed valve 4t2, haying' an actuating coil Om is associated with the outer end ci the cylinder 40, while a normally open valve 43, having an actuatingcoil 0th c''ects communication with the outer end of the other cylinder 4l. A plurality of supply pipes 44C and l5 respectively convey fluid pressure to the valves 4t2 and t3 from any suitable source (not shown).

The me=.'=hanical operation ot' the device just described may he set forth as follows. By reason of the normal admission of fluid pressure to the cylinder 41, the apparatus is initially biased to the illustrated position. Upon the concurrent energization ot the actuating coils On and Off, such initial unbalanced fluid-pressure conditions are reversed; that is, fiuid pressure is admitted through the valve Ll2 to the cylinder f-O and is exhausted trom the cylinder l through the valve 43 to the atmosphere. Consequently, a movement ot` the controller G (in the illustrated case toward the right) ensues. To arrest such movement at any time, it is merely necessary to denergize the oil'l coil, whereupon balanced high-pressure-fluid conditions exist in the mechanism, and a positive and reliable stoppage thereot' is effected.

To produce a return movement of the apparatus, the actuating` coils On and Oft are concurrently denergiced, whereby fluidpressure conditions revert to the original state and the desired backward movement is effected.

The torque-motor relay device 8 comprises an armature winding 50, upon the shaft 5l of which is mounted a small drinn or cylinder 52 that carries na plurality ot contact segments 53 and 54: ot' appropriate configuration for effecting certain auxiliarycircuit connections, to be subsequently7 described, in accordance with the occupation of its positions fr, y and e' by the relay device. A plurality of centering springs 55 bias the relay device S to its illustrated intermediate position y. An exciting field winding, having a plurality ot sections 5G and 5T, provided tor the relay armature 50, the sections 56 and 57 being respectively connected across the main-current-excited field Yw` iding 25 of the exciting armature 22 and across the armature 22 itself.

The field-winding sections 56 and 57 are differentially related for a purpose to be set forth, the unidirectionally excited section 57 normally predominatin'. The relay armature 5G is connected through a voltage-reducing resistor 58 and an electrical interlock 9-out, ot a familiar type, across the terminals of the switch 9, whereby the armature 50 receives the difiierence between the supplycircuit voltage and the main-machine voltage during the coasting period and is consequently actuated in the one or the other direction in accordance with the temporarily greater voltage. The relay device 8 is adapted to govern the actuatin mechanism 7 for the controller' 6, thus serving to vary the illust-rated circuit connections in accordance with the relation of the two voltages just mentioned.

The solenoid-type main-eld-fiux relay 12 has its actuating coil connected in series relation with the main-current-excited field winding 25 for the generator armature 22 and with the section 56 of the torque-motor relay-device field winding. The relay l2 is thus energized in accordance with the voltage fluctuations or changes of the auxiliary field winding 25, which fluctuations occur synchronously with the changes ot mailifield-winding-fiux. Such changes occur, to a considerable degree, during the preliminary regulating period prior to connection of the main machine to the supply circuit, and the object of the relay l2 is to prevent such connection until main-field-f'lux conditions, as reflected by the voltage across the main-c rient-excited field winding are substantially stable. The main-field-tlux relay 12 is provided with a bridging contact member 59 for closing, in its lower position, certain auxiliary circuits to be described.

i'fissuining that regenerative operation, for example, has been begun, the various circuit connections may be traced as follows. rl`he main-armature or regenerative circuit, indicated by the solid arrows, is established from the supply-circuit conductor Ground through conductor 60, the exciting field winding 25 tor the generator armature 22, conductors 6l, 62 and 63 and junction-point G4, where the circuit divides, one branch including stabilizing resistor 4, conductor 65, accelerating resistor 5, main armature fil and conductor 66 to a second junctiorpoint 67, and the other b anch traversing stabilizing resistor 3, conductors (i8 and (il, main armature A2, conductor 70, accelerating resistor 2, and conductor Tl to the junction-point (3T, whence a common circuit is completed, through conductor "f2, switch f), and conductor 7f3, to the trolley.

The exciting or main-field-winding circuit, indicated by the dotted arrows, is established from the positive terminal ot the exciting armature .22 through conductors '75, (S2 and G3, to the junction-point 611i, where the circuit divides, one branch traversing stabilizing resistor l, conductor (S5, main field winding Fl, and conductor 76, to a rothcr junction-point 77, and the other bra uch including stabilizing resistor 3, conductor 68, main field winding F2 and. conductor 2'8 to the junction point T7, whence circuit is completed through conductor f) to the negative terminal ot' the generator armature An auxiliary circuit is cstablishe( troni the trolley conductor 73 through conductor 80, field winding and auxiliary exciting armature 2f), conductor Sl, exciting field windings 24; and 25 tor the generator armature 22, and thence, through conductor (30, to ground.

The main armatures A1 and A2 are thus connected in series relation with the pairs ot resistors 4; and 5, and 2 and 3, respectively, the two main-armature circuits being connected in parallel relation across the supply circuit. rlhe exciting armature 22 is connected to send current through the stabilizaing resistors 3 and et in the same direction lOO as the corresponding main-armature current, while the main field windings F1 and lf2 are energized solely from the exciting armature 22.

Reference may now be had to Fig. 2, wherein the auxiliary governing system shown comprises the actuating coils otl the switches 9, 1() and 11, the actuating coils On and Oil", the auxiliary contact members ot the torque-motor relay device 8 and ot the main-eld-flux relay 12, together with a master controller MC and a suitable source of auxiliary energy, such as a battery B, for primarily governing the control system, and a plurality of push buttons 90 and 91, or the like, for permitting a certain manual regulation of the system, irrespective oit the operating position of the master controller,

Assuming that the main machines have been accelerated and are now coasting under transitory normal-speed conditions, in preparation for machine operation, regeneration may be effected by actuating the master controller MC to its initial regenerative position c', whereby certain auxiliary circuits to be traced are closed in accordance with the position of the torque-motor relay device 8.

Vhenever the supply-circuit voltage is temporarily greater than the momentumdriven machine voltage, the resultant traversal ot current through the armature 5() ot the torque-motor relay device 8 causes the relay device to move to its position e, .vhereby one auxiliary circuit is established from the positive terminal of the battery B through conductor 92, control lingers and 94, which are bridged by contact segment 95 of the master controller, conductor 9G, the actuating coil Ott', conductor 97, Contact segment 53 ot the relay device 8, and corduetors 98 and 99 to the negative terminal oi the battery B.

A similar circuit is completed Yfrom the Contact segment 95 ot the master `controller, through control linger 100, conductor 101, actuating coil 0n, conductor 102, and thence, through one Contact segment 53 of the relay device 8, as just traced. By reason of such concurrent energization ot the actuating coils 0n and Oft', a forward movement ot the controller 6 occurs to initially exclude the accelerating resistors 2 and 5 from the circuits ot the respective armatures and, subsequently, to gradually reduce the activecircuit values ot the stabilizing resistors 3 and l, whereby the voltage ot the main machines is increased to a. value approximately equal to that ot the supply-circuit voltage, dependent upon the design ot the component elements of the system.

On the other hand, whenever the machine voltage, during transitory normal-speed coasting` conditions, emporarily predominatesA over the supply-circuit voltage, the consequent reversal of current through the armature 50 ot the relay device S causes the relay device to be actuated to its position wherein the energizing circuits for the actuating coils @n and @il are both interrupted to ellect a return movement ot the controller in accordance with the previously described principles, thereb., gradually inr easing the active-circuit values ot the resistors 3, 1'- and 5 and, consequently, reducing the main-machine voltage to the desired value.

1lllhen the supply-circuit voltage and the main-machine voltage have attained the desied approximately equal relation, the torque-motor relay device 8 occupies its intermediate position 5y, and,` as soon as mainield-llux conditions have become substantially .v ble to permit the relay 12 to assume its lower position, a further auxiliary circuit completed `trom the contact segment 95 ot the master controller through control .ingef' 10i-. fonductor 104, the actuating coil ot the lin(` switch 9. conductor 105, contact segment 5l oi' the relay device S, conductor 10G, bridging contact member 59 of the main-iield-liux relay l2. and conductor 99 to the negative battery terminal.

lt desired. the closure ot the line switch 9 may be utilized to open the circuit ot the relay fmature 5G through. the agency ot the electrical interlock Sli-out, whereby the relay device remains in its intermediate position and no current traverses the relay armature.

Under normal accelerating or regenerative lfonditions., the main-iield-flux relay 12 will romain in its lower circuit-closing position to maintain the closed condition ot the line 9, ilthough, it desired, an electrical iterloclr ,0f-in, ot the well-known type simiar to that illustrated, may be employed to bridge the auxiliary Contact members ot the relay 12.

Assuming that, hy reason ol deseencing a rade du ing tht` transitory coasting period, ic momentum-driven machines attainl a latively high speed-and that it would involve a heavy surge ot current and possible injury to the machines to connect them to the supply circuit under such high-speed conditions. the torque-motor relay devi-ee 8 will inherently operato to prevent such connection.

Although, under the high-speed conditions mentioned, an excessive machine voltwill result as soon as the main field windings are fully energized, nevertheless, initially, the supply-circuit voltage is greater than the machine voltage, which tends to move the torque-motor relay device S in the direction to reduce the active-circuit values of the resistors 2, 3, 4 and 5 and thus strengthen the main field excitation, whereas a weakening` thereof is, in fact, necessary. It the switch 11 is opened to insert the auxiliary `itield winding 24C in circuit and thus build up the voltage of the generator armature 22, the section 57 of the field winding for the torque-motor relay device 8 is at first weakly energized, while the differentiallyrelated section 56 is rather strongly excited by reason of the changes of field-flux conditions that occur in the auxiliary field winding 25 for the generator armature 22. The resultant excitation of the relay armature 50 is either sufficient to maintain the relay device in its intermediate position or it is actuated in the opposite direction toward its position to weaken the main fieldexcitation, as desired. By reason of this inherent counteracting effect in the torquemotor relay device 8 under relatively highspeed coasting conditions, the connection of the main machines to the supply circuit is prevented until electrical conditions in the main machine are entirely suitable therefor.

1f it is desired to short-circuit the maincurrent-excited field winding 25 for the exciting armature 22 during regular operation of the main machines and thus employ the auxiliary field winding only during the transitory reguating period, such action may be accomplished by actuating the push-button 91 to, and suitably holding it in, its lower or closed position, whereby a circuit is completed from the Contact segment 95 of the master controller through control finger 107 the actuating coil of the switch 11, conductor 108, push-button 91 and conductors 109 and 110 to the negative conductor 99.

Furthermore, it is preferable to short-circuit the allied auxiliary field winding 24C during the general coasting period and thus reduce the energy losses of the motor-generator set. Such a result may be effected by closing the push-button 90, whereby the circuit is completed from the contact segment 95 of the master controller in its off position through control finger 111, the actuating coil of the switch 10, conductor 112, push-button 90 and conductor 113 to the negatively-connected conductor 110.

To effect further regulation of the controller 6, after the main machines have been connected to the supply circuit, the master controller may be moved to its position whereby a new circuit is completed from the lower terminal of the off coil, through conductor 1111, control fingers 115 and 116, which are bridged by contact segment 117 of the master controller, and conductor 11:` to the conductor 113 and thence to the negative battery terminal. By thus intermittently energizing the off coil,aforward stepby-step movement of the controller 6 may be effected to gradually reduce the activecircuit value of the resistors 2, 3, l and 5 and thus compensate for the gradual decrease of period.

speed during the retardation Inasinuch as the accelerating operation of the system is similar to that previously set forth and will be readily understood by those skilled in the art, no detailed exposition thereof is deemed necessary.

In lieu of employing the auxiliary field winding 25 for the purpose of preventing the connection of t-he main machines to the supply circuit until 1nain-field-excitation conditions are relatively stable, it will be kunderstood that other equivalent circuit connections may be employed, if desired. For example, an auxiliary coil wound upon the polar projections of one of the main machines may be substituted for the auxiliary field winding 25. In this case also, flux changes of the main field winding will be reflected in the auxiliary coil to maintain the relay 12 in its upper or open-circuit position until the desired stable conditions ol tain.

Furthermore, the desired torque-relay action may be Obtained by interchanging the connections of the relay armature 50 and held-winding section 57.

Reference may now be had to Fig. 3, wherein the system shown comprises the supply-circuit conductors Trolley and Ground and a main dynamo-electric machine having an armature A1 and field winding F1; together with an auxiliary motor-generator set 201; a torque-motor relay device 202; a shunt transformer 203; a stabilizing resistor 204, which may be varied in active circuit value by means of a controller 205 `having the previously-described actuating mechanism 7; an auxiliary-circuit resistor 206; a line-switch LS; and an auxiliary source of energy, such as the battery B.

The 'motor-generator set 201 is shown as comprising a driving or motor armature 210; a generator or exciting armature 211 which may be coupled to the driving armature by a. shaft 212, for example; a seriesrelated field winding 21S-3 for the driving armature and a field winding 214: for the exciting armature 21-, the field winding 214 being' shunted by a surge-absorbing resistor 215 and being connected in series relation with the auxiliary driving motor.

The torque-motor relay device 202 comprises a commutator-type armature 216 and a supply-circuit-excited field winding 217 therefor. The relay shaft 21S carries a small drum or cylinder 219 upon which are mounted a plurality of auxiliary-circuit contact segments 220 and 221 for effecting various circuit connections to be set forth, in accordance with the occupation of positions a, b or c by the relay device. A plurality of centering springs 222 bias the relay to its illustrated intermediate position Z).

The transformer 203 comprises a primary uf'inding 225 that is connected through the voltage-reducing resistor 206 across the main armature A1 and a secondary winding 226 that is connected in series relation with the armature 216 of the torque-motor relay device across the line switch LS.

The relay armature 216 thus receives the difference of supply-circuit voltage and main-armature voltage during the coasting period, and is concurrently energized in accordance with the rate and direction of change of the main field flux or armature voltage by reason of the circuit connection of the transformer 203, as hereinafter set forth in detail.

The two transformer windings are wound to oppose each other and consequently, under conditions of a relatively rapid increase or decrease of the difference between the supply-circuit voltage and the armature voltage, the main-tield-winding flux, as reflected in the primary transformer winding 225, quickly increases in the one or the other direction to thus inherently introduce a voltage opposing the relay-armature voltage in the secondary transformer winding 226, for a purpose to be set forth.

The controller 205 is provided with a multiposition contact segment 227 for successively engaging a plurality of control fingers 22S that are connected to predetermined points of the stabilizing resistor 20-1, whereby the resistor may be gradually excluded from circuit during the regenerative period to increase the main-field-winding excitation and compensate for the gradual decrease of main-machine speed.

Assuming that the line switch LS has been closed, the main-armature or regenerative circuit, indicated by the solid arrows, is established from the supply-circuit conductor Ground through conduct-.ors 230, 231 and 232, junction-point 233, conductor 23a, main armature A1, conductors 230 and 237, line switch LS, and conductor 23S to the trolley.

The exciting or main-field-winding circuit is established from the positive terminal of the auxiliary generator armature 211 through conductor 210, stabilizing resistor 201, conductor 232, junction-point 233, main field winding F1 and conductor to the negative terminal ofA the exciting armature.

An auxiliary circuit is completed from the trolley through conductors 23S, 242 and 243, field windings 214 and 213 for the auxiliary armatures 211 and 210, respectively, the auxiliary driving armature 210 and conductor 24A to ground.

Under transitory coasting conditions of the main machine, when the line switch LS is open and just prior to the connection of the machine to the supply circuit, the controller 205 is automatically governed by the torque-motor relav device 202 to maintain a balance of the supply-circuit voltage and the main-armature voltage in the following manner: 1f the supply-circuit voltage temporarily exceeds the main-armature voltage, the relay device 202 is actuated to one extreme position t to complete a circuit from the positive terminal of the battery B through hand-switch 2419 and conductor 250 to a junction-point 251, where the circuit divides, one branch including conductor 252, contact segment 220 of the torque-motor relay device in position a, conductor 253, the actuating coil On for the controller 205 and conductor 25-1 to the negative battery terminal. Another circuit is continued from the contact segment 220 through conductor and the actuating coil Off to the negative conductor 254:.

Since both actuating coils for the operating mechanism 7 are concurrently energized, forward movement of the controller 205 occurs to gradually short-circuit the stabilizing resistor 2041 and thus increase `the mainfield-winding excitation and the main-armature voltage.

On the other hand, if the main-armature voltage temporarily predominates over the supply-circuit voltage, the torque-motor relay device 202 is actuated to its other extreme position c. whereby both actuating coils On and Off are denergized to effect a backward movement of the controller 205 and thus weaken the main field excitation and reduce the main-armature voltage to the desired value.

One of the advantages of the present system is that it effects a reduction in the timeelement necessary for balancing the supplycircuit voltage against the main-armature voltage during the coasting period before connection of the machine to the supply circuit, and in this respect the system of Fig. 3 is an improvement over the previouslydescribed system that is shown in Fig. 1. lllhereas, in the system first described, oversliooting of the controller for governing the main field-excitation could occur, thus delaying the desired balanced condition of the supply-circuit voltage and the 'main-armature voltage, in the present system such undesirable operation is effectively avoided and, moreover, the transformer 203 actually operates to expedite the arrival at a balanced-voltage condition in the following way.

Assuming, for instance, that the mainmachine voltage during the coasting period is quickly rising toward a value equal to the supply-circuit voltage, a correspondingly increased current traverses the primary winding 226 of the transformer` to cause an increase of flux in a certain direction in the secondary winding 225, which is connected in circuit to oppose the voltage of the relay-device armature 2 16. The relayarmature voltage, in this way, will decrease to substantially Zero value betore the mainarmature voltage actually equals the supply-circuit voltage. Thus, the torque-motor relay device will assume its intermediate position to close the line switch, in accordance with the circuit about to be traced, without causing` unnecessary regulation ot the controller whereby the total timeint lrval necessary tor connecting the main machine to the supply circuit after movement of a governing controller by the train operator is reduced to a relatively small value.

r1`hc auxiliary circuit just mentioned for effecting the closure ot the line switch is established from the positively-energized conductor 2.30 through conductor 256. contact segment 221 ot' the relay device in its intermediate position conductor 257 and the actuating coil of the line switch LS to the negative conductor 2541-.

On the other hand, if the main-armature voltage is assumed as already above the line voltage and as rapidly increasing to a still greater value, the resultant increase of flux in the transformer 203 acts in the opposite direct'on, since the relay-armature voltage is now oit the opposite polarity from the case previously assumed, to again oppose the ditferencc oi supply-circuit and main-armature voltage, that is, the voltage of the relay armature 216, and thus rapidly bring about the desired balanced-voltage conditions that cause the closure of the line switch.

Two other cases may arise: namely, a rapid decrease of main-field flux to vary the main-armature voltage either away from or to vard the concurrent value oit supply-circuit voltage. 1n the former case, the relayarmature voltage is positive with respect to the supply circuit and will be inherently decrez-ised by the action ot the transformer 203. and in the latter case, the relay armature voltage, ot the opposite polarity, will again be opposed or decreased by such inherent action. .ln other words, the illustrated combination of torque relay and transtormer inherently acts under all transitory coasting conditions just prior to the connection of the main machine to the supply circuit to expedite the desired balancedvoltage conditions and the closure .of the line switch, by always opposing the relayarmature voltage irrespective of its polarity.

after the closure ot the line-switch, the relay device 202 remains in its mid-position, whereby the circuit of the off coil is deenergiyed to cause the controller 205 to remain stationary. Subsequent regulation oi the controller to compensate for the decrease of vehicle speed may be accomplisl ed by the addition of suitable auxiliary circuits, as will be understood by those skilled in the art, without further cescription.

1t will be appreciated that other equivalent connections of the transformer 203 may be employed for decreasing the above-mentioned time-interval for balancing` the dcsired voltages. For example, the primary transformer winding 226 may be connected across the main field winding F1, while the secondary transfr'irmcr winding 225 may be connected in series relation with the field winding` 21T Jfor the torque-motor relay device. onsetpiently, 1 do not wish to be restricted to the specific circuit connections or arrangement ot' parts herein set forth, as various other modiiications thereof may be effected without departing from the spirit and scope ot my invention. 1 desire, theretore. that only such limitations shall be iinposed as are indicated in the appended claims.

l claim as my invention: y

l. ln a system ot.' control, the combination with a supply circuit and a dynamoelectric machine having` an armature and a l ld winding, ot means tor varying` the fiel excitation in accordance with predetermined machine conditions, and means tor automatically counteracting said varying means under predetermined transitory machine conditions.

2. ln a control system.. the combination with a supply circuit and a dynamo-electric machine having an armature and a field winding.` ot means for varying the field excitation in accordance with the relation of .supply-circuit voltage and armature voltaeje under certain transitory coasting conditions and 'tor inherently effecting an action ojposing said means under predetermined other transitory conditions.

2E, ln a control system, the combination with a supply circuit and al dynamo-electric machine havingl an armature and a Yfield winding, oi' electrical relay means tor varying the field excitation in accordance with the relation o't' supply-circuit voltage and armature voltage under certain transitory coasting' conditions and Yfor inherently introducing an opposing magneto-motive torce in a winding ot said relay means under predetermined electrical conditions ofi said field winding.

1n a control system, the combination with a supply circuit and a main dynamoelectric machine having` an armature and a field winding, ot a torque-motor relay deie d vice having` a cooperating armature andv field winding tor varying the main field excitation in accordance with the relation of" supply-circuit voltage and main arn'iaturc voltage under certain transitory coasting conditions and iior inherently introducing an opposing magneto-motive torce in a field winding ot said relay device under predeterniined varying conditions ot the maini'ield winding flux.

5. 1n a system of control, the combination with a supply circuit and a dynamoelectric machine having an armature and a field Winding, of a relay device for governing certain circuit connections of said machine in accordance With the relation of supply-circuit voltage and machine voltage, and a winding influenced in accordance with the main-field-Winding flux for controlling said relay device.

6. In a system of control, the combination with a supply circuit and a dynamoelectric machine having an armature and a field Winding, ot means for varying the field excitation under certain transitory coasting conditions in accordance With the relation ot supply-circuit voltage and machine voltage, and means for automatically counteracting such variation under certain other transitory coasting conditions.

7. In a system of control, the combination with a supply circuit and a dynamoelectric machine having an armature and a field ninding, of relay means for varying the field excitation under normal-speed coasting conditions to produce a'predeterl j, mined relation of supply-circuit voltage and machine voltage, and means for oppositely influencing said relay means to counteract suoli variation under relatively high-speed coasting conditions.

S. In a system of control, the combination ivith a supply circuit and a dynamoelectric machine having an armature and a field Winding, of a torque-motor relay device for regulating the field excitation under normal-speed coasting conditions to produce a predetermined relation of' supplycircuit voltage and machine voltage, and additional exciting means for said relay device for counteracting such regulation under relatively high-speed coasting conditions.

9. In a system of control, the combination ivith a supply circuit and a main dynamo-electric machine having an armature and a field Winding, of an exciting machine for the main lield Winding, an auxiliary field Winding for said exciting machine, and a torque-motor relay device having an armature and a plural-section field Winding for automatically regulating the main field excitation under normal-speed coasting condi. ions to produce a predetermined relation oi supply-circuit voltage and machine voltage, one section of the relay field winding being differentially energized from said field Winding for the exciting machine.

l0. In a system of control, the combination vvith a supply circuit and a dynamoelectric machine having an armature and a Winding, of means 'for varying the field excitation under transitory coasting conditions in accordance With the relation of supply-circuit voltage to machine voltage, a relay device normally acting in conjunction with said varying means for modifying certain circuit connections, and a Winding energized in accordance With the mainfield-vvinding flux for preventing such action of the relay device until main-field- `Winding conditions are substantially stable.

ll. In a system of' control, the combina` tion with a supply circuit and a dynamoelectric machine having an armature and a field Winding, of a torque-motor relay device for regulating the eld excitation under normal-speed coasting conditions to produce a predetermined relation of supply-circuit voltage and machine voltage, a relay normally acting in conjunction With said varying means for effecting the connection of the machine to the supply circuit, and an auxiliary field Winding energized in accordance with the main-field-Winding flux for pre venting such action of the relay until mainfield-winding conditions are substantially stable.

12. In a system of control, the combination ivith a supply circuit and a main dynamo-electric machine having an armature and a field Winding, of an exciting machine for the main field Winding, an auxiliary field winding for said exciting machine, a torque-motor relay device having an armature and a field Winding for automatically regulating the main field excitation under normal-speed coasting conditions to produce a predetermined relation of supply-circuit .'oltage and machine voltage, and a relay for governing certain circuit connections, said relay having an actuating coil connected in circuit with said field Winding for the exciting machine and vvith the relay-device field Winding.

13. In a system of control, the combination with a supply circuit and a dynamo-electric machine having an armature and a field Winding, of means for varying the field excitation under norm :il-speed transitory coasting conditions in accordance With the relation of supply-circuit voltage to machine voltage, a relay device normally acting` in conjunction ivith said varying means for modifying certain circuit connections, a winding energized in accerdance ivitli the main-field-Winding flux for preventing such action of the relay device until main-field Winding conditions are substantially stable, and means for oppositely influencing said varying means under relatively high-speed coasting conditions.

la. In a system of' control, the combination ivith a supply circuit and a dynamoelectric machine having an armature and a field Winding, of a torque-motor relay device for regulating the field excitation under normal-speed coasting conditions to produce a predetermined relation of supply-circuit voltage and machine voltage, a relay normally acting in conjunction ivith said torquedl O motor relay device for 'effecting the connection of the machine to the supply circuit, an auxiliarv field winding energized in .accordance ith the main-field winding 'flux for preventing such action of the relay until maii-lield-winding conditions are substantially stable, and additional exciting means for said relay device for counteracting said regulation under relatively high-speed coasting conditions.

l5. ln a system of control, the combination with a supply circuit and a main dynamoelectric machine having an armature and a field Winding, of an exciting' machine for the main field winding, an auxiliary eld winding for said exciting machine, a torqueinotor relay device having an armature and a plural-section field Winding for automatically regulating the main field excitation under normal-speed coasting conditions to produce a predetermined relation ot supplycircuit voltage and machine voltage, and a relay for governing the connection ol' the machine to the supply circuit in conjunction with said relay device and having an actuating coil connected in circuit with said field winding for the exciting machine and with a difierentially-energized section of the relaydevice tield winding..

1G. ln a system ot control, the combination with a supply circuit and a dynamoelectric machine, ot' a torque-motor relay device for governing certain machine connections, said device having one winding uniilirectionally excited and having another winding excited in accordance with the ditt'erence of the supply-circuit voltage and the machine voltage.

1T. In a system orl Control, the combination with a supply circuit and a dynamoelectric machine, of a torque-motor relay device ior governing certain machine connections, said device having an armature winding excited in accordance with the difference of the supply-circuit voltage and the inacliine voltage and having a field winding provided with a plurality ot' sections that are respectively energized in accordance with the main-armature current and the mainfield-winding voltage.

18. In a control system, the combination with a. supply circuit and a dynamo-electric machine having an armature and a field winding, ot means for varying the field excitation in accordance with the relation or' supply-circuit voltage and armature voltage under certain transitory coasting conditions, and means tor inherently opposing the action of said varying means under predetermined lux conditions of said field winding.

l?. ln a control system, the combination with a supply circuit and a dynamo-electric machine having an armature and a field winding, ot means for varying the field excitation in accordance With the relation ot supply-circuit voltage and armature voltage under certain transitory coasting conditions, and means connected to inherently effect an action opposing said varying means when he main-armature voltage value is relatively rapid y appro ching toward, or receding trom, the simultaneous supply-circuit voltage value.

2l). In a control system, the combination "h a supply circuit and a dynamo-electric machine having an armature and a field winding, of a torque relay device having one ci its elements energized in accordance with the difference ot supply-circuit voltage and armature voltage under certain transitory coasting conditions, means governed by said ay device for varying the field excitation, n eans dependent upon predetermined relaydevice conditions for er'lecting the connection ot said machine to the supply circuit, and a field winding connected to oppose the ciiect ol said voltage difference under predetermined field-flux conditions.

2l. ln a control system, the combination with a supply circuit and a dynamo-electric machine having an armature and a field inding, of means for varying the field exztion in accordance with the relation of supply-circuit voltage and armature voltage under certain transitory conditions and also in accordance with the rate or' change oi? main-field-Winding flux under other transitory conditions.

ln a control system, the combination with a supply circuit. and a dynamo-electric ma chine having an armature and a field inding, oi? relay means for varying the field excitation in accordance with the relation ol supply-circuit volt-age and armature voltage under transitory coasting conditions acconipanied by a relatively slow rate ot change ot the main field-winding flux and also in accordance with the rate ot change ot such linx under relatively rapidly changing conditions thereof.

23. ln a control system, the combination with a supply circuit and a dynamo-electric machine having an armature and a field wind ing, oi means 'for varying the field exctation in accordance with the relation oi" supply-circuit voltage and armature voltage under certain transitory coasting conditions, and means connected to inherently oppose the effect of the difference or such voltages irrespective of the polarity thereof in accordance with predetermined variations of field-winding flux.

T24. ln a control system, the combination. with a supply circuitl and a dynamo-electric machine having an armature and a field winding, ot' a torque relay device for varying the field excitation and having one ot its component elements energized in accordance with the diderence of supply-circuit voltage and main-armature voltage under certain transitory coasting conditions, and means connected to inherently oppose the effect of said difference irrespective of its polarity under conditions of a relatively rapid rate of change of the field-Winding linx.

25. In a system of control, the combination with a supply circuit and a dynamoelectric machine, oi' means for regulating a machine circuit during predetermined stable relations of certain electrical conditions of said supply-circuit and said machine, and means for differently regulating said circuit during unstable transitory relations of said conditions.

26; In a system of control, the combinationA with a supply circuit and a dynamoelectric machine, of means for regulating a machine circuit during predetermined stable relations of the supply circuit and the machine voltages, and means for counteracting such regulation during unstable transitory relations of said voltages.

27. In a system of control, the combination with a supply circuit and a dynamoelectric machine having an armature and a iield Winding, of a relay device for regulating the field excitation during predetermined stable relations of the supply-circuit and the machine voltages and for counteracting such regulation during unstable transitory relations of said voltages.

2S. In a system of control, the Combination With a supply circuit and a dynamoelectric machine, of a torque-motor relay device having a coperating armature and field Winding for regulating a machine circuit during predetermined stable relations of the supply-circuit and the machine voltages, and means for counteracting such regulation during unstable transitory relations of said voltages.

In testimony whereof, I have hereunto subscribed my name this 30th day of August 191 RUDOLF E. HELLMUND. 

